A fluorosulfonyl group-containing polymer having units represented by the following formula u1, a sulfonic acid group-containing polymer having fluorosulfonyl groups in the fluorosulfonyl group-containing polymer converted into sulfonic acid groups, its production method and its applications: ##STR00001##
wherein R.sup.F1 and R.sup.F2 are a C.sub.1-3 perfluoroalkylene group.

A fluorosulfonyl group-containing polymer having units represented by the following formula u1, a sulfonic acid group-containing polymer having fluorosulfonyl groups in the fluorosulfonyl group-containing polymer converted into sulfonic acid groups, its production method and its applications: ##STR00001##
wherein R.sup.F1 and R.sup.F2 are a C.sub.1-3 perfluoroalkylene group.

A method for producing a fluorosulfonyl group-containing compound to obtain a compound represented by the following formula 5 from a compound represented by the following formula 1 as a starting material and a method for producing a fluorosulfonyl group-containing monomer in which the fluorosulfonyl group-containing compound is used:

##STR00001##

wherein R.sup.1 and R.sup.2 are a C.sub.1-3 alkylene group, and R.sup.F1 and R.sup.F2 are a C.sub.1-3 perfluoroalkylene group.

Described herein is method of making branched perfluorinated compounds, specifically (CF.sub.3).sub.2CFCF(CF.sub.3)OCF(CF.sub.3)C(═O)F and (CF.sub.3).sub.2CFCF(CF.sub.3)OCF═CF.sub.2. Also disclosed herein is a fluoropolymer derived from the branched perfluorovinyl ether monomer and methods of making the fluoropolymer.

Described herein is method of making branched perfluorinated compounds, specifically (CF.sub.3).sub.2CFCF(CF.sub.3)OCF(CF.sub.3)C(═O)F and (CF.sub.3).sub.2CFCF(CF.sub.3)OCF═CF.sub.2. Also disclosed herein is a fluoropolymer derived from the branched perfluorovinyl ether monomer and methods of making the fluoropolymer.

Described herein is a polymerizable composition substantially free of an organic emulsifier, methods of making, and articles thereof. The polymerizable composition comprises: a continuous phase; a polymerizable monomer; an initiator; and inorganic nanoparticles, wherein the inorganic nanoparticles are substantially free of groups that will copolymerize with the polymerizable monomer.

Described herein is a polymerizable composition substantially free of an organic emulsifier, methods of making, and articles thereof. The polymerizable composition comprises: a continuous phase; a polymerizable monomer; an initiator; and inorganic nanoparticles, wherein the inorganic nanoparticles are substantially free of groups that will copolymerize with the polymerizable monomer.

Provided is a fixing member having an outer surface including excellent toner releasability and excellent scratch resistance, wherein the fixing member has a base material, an elastic layer, and a release layer in this order, the release layer including a tetrafluoroethylene/perfluoroalkyl vinyl ether copolymer, and has a loss tangent at a frequency of 10 Hz and 180 C. of 5.010.sup.2 or more and 3.010.sup.1 or less.

Provided is a fixing member having an outer surface including excellent toner releasability and excellent scratch resistance, wherein the fixing member has a base material, an elastic layer, and a release layer in this order, the release layer including a tetrafluoroethylene/perfluoroalkyl vinyl ether copolymer, and has a loss tangent at a frequency of 10 Hz and 180 C. of 5.010.sup.2 or more and 3.010.sup.1 or less.

A monomer having formula (I):

##STR00001##

wherein in formula (I), groups and variables are the same as described in the specification.